Method for making a pre-testable semiconductor die package

Abstract

An encapsulated die package (20) is shown in which a semiconductor die is connected in a die-attach aperture of a copper foil tape (11). Die contact pads (31) are bonded to the inner ends (31a) of interconnected finger contacts (13) on the tape. Finger contacts etched in the foil include splayed out portions (15) extending to probe ends (19). Interconnect cross-links (16) initially connect the finger contacts and the tape edges and function as dam bars in subsequent encapsulation steps. The die and die bonds are mold encapsulated to form the die package (20) and a carrier frame (17) is simultaneously molded around and spaced from the periphery of package (20). The probe ends are exposed within a slot (34) in the frame or extend from the ends of the frame so that probe tips can be pressed thereon to test the die and its bonds. Prior to testing, the interconnects exposed in the annulus between the package and the carrier are blanked out so that each finger leading from a die contact pad becomes discrete, i.e. is no longer interconnected to an adjoining finger, so that testing of each die contact and bond can be done. The stiff molded carrier acts to support the probe ends of the fingers and protects and stiffens the foil tape for the testing operations and for shipping and handling purposes.

I claim: 
     
       1. A method of fabricating a tapemounted semiconductor die package testable in-situ comprising: providing a metal foil lead frame having multiple interconnected finger contacts extending from a die-receiving area, said contacts having inner beam ends, outer test ends and intermediate portions therebetween including cross-links connecting said finger contacts;   connecting contact pads of a semiconductor die to said inner beam ends;   molding a package-forming encapsulant around said die and said inner beam ends on said lead frame whereby said outer test ends and intermediate portions of said finger contacts extend outwardly from said encapsulant;   molding an insulative carrier over at least a transverse part of said outer test ends of said finger contacts while leaving said outer test ends exposed whereby electrical probe contact can be made to said finger contacts; and   removing said cross-links from their location between said finger contacts whereby said outer test ends become electrically isolated and are accessible for probe testing individual ones of said finger contacts adjacent said carrier.   
     
     
       2. The method of claim 1 further comprising trimming away said carrier and all of said lead frame so as to leave said package with said intermediate portions of said finger contacts extending from said package-forming encapsulant to form said die package. 
     
     
       3. The method of claim 1 in which said metal lead frame is processed in the form of a metallic single-layer foil strip with a plurality of interconnected successive linear arrays of multiple interconnected parallel finger contacts and die-receiving areas and wherein said molding steps are simultaneously performed on said plurality of arrays in said strip. 
     
     
       4. The method of claim 3 including aligning a series of dies with respect to each of said arrays in said strip; and bonding a die to each of said arrays. 
     
     
       5. The method of claim 1 further comprising molding said carrier peripherally in the form of a ring around and spaced from said package-forming encapsulant, said transverse part extending between and providing backing for said outer test ends and lying outside said cross links which are thereby exposed in the region of said intermediate portions of said finger contacts. 
     
     
       6. The method of claim 1 further comprising daming an area of said insulative carrier during said molding step transverse of said finger contact outer test ends thereby to exclude a portion of said carrier and to form a probing slot that exposes said outer test ends of said fingers in said carrier transverse to said outer test ends. 
     
     
       7. The method of claim 1 wherein said die is connected to said inner beam ends by thermal compression gang bonding. 
     
     
       8. The method of claim 5 wherein said carrier ring is made thicker than said package-forming encapsulant whereby the molded carrier acts to protect said package during handling and testing. 
     
     
       9. The method of claim 5 wherein said carrier ring is molded simultaneously with said package-forming encapsulant.